Britain and Brussels are back at loggerheads as a fresh row emerges over the size of the Brexit divorce bill.

European Union accounts put the new net figure for the financial settlement as £40.8 billion, at least £1.8bn more than the highest UK estimate for the payments.

Downing Street rejected the figure on Friday and doubled down on its previous estimates of between £35 billion and £39 billion. More details would be presented to Parliament in the near future, it said

The dispute comes hot on the heels of a string of clashes since the UK left the Single Market and Customs Union at the end of last year.

The UK and European Commission have fought over vaccine supplies, Northern Ireland, fishing rights and come close to triggering a trade war over sausages.

Both sides agreed a method for calculating what was owed by the UK after 47 years of membership but did not settle on an exact figure in the Brexit negotiations.

"We don’t recognise that figure, it’s an estimate produced by the EU for its own internal accounting purposes," a No 10 spokesman said.

"For example, it doesn’t reflect all the money owed back to the UK, which reduces the amount we pay. Our estimate remains in the central range of between £35 and £39 billion and we will publish full details in Parliament shortly."

In Brussels, a European Commission spokesman said the new figure was "correct".

"The report is final and the calculations were made in line with the withdrawal agreement," he said.

"We have already informed the UK Government about the payments that they have to do with regard to the first part of this year and they’ve already in fact paid part of the amount concerned.

"Therefore, we have absolutely no indications at this point in time that the bill, or the amount that we’ve calculated, will be contested."

MPs tell Boris Johnson to stand firm

Tory backbenchers urged Boris Johnson to stay firm in the face of Brussels.

David Jones, the deputy chairman of the European Research Group of Tory MPs, said "This is typical of the European Union, pushing this stuff out in a bid to up the ante and to stoke animosity", while Andrew Bridgen, the North West Leicestershire MP, added: "It comes as no surprise that the EU wants to screw every penny out of us and the bill is going up and up."

He said the row would lead to calls for the UK to "walk away" from the Withdrawal Agreement.

Theresa Villiers, a former environment secretary, said: "Throwing around excessive figures like these does not demonstrate a realistic or constructive approach from the EU. Pragmatism and mutual respect, not posturing, is what is needed."

The EU accounts, which are yet to be signed off by auditors, revealed that the UK is to pay £5.8 billion to Brussels this year.

The Office for Budget Responsibility (OBR) estimated the total bill to be £37.1 billion in 2018.

The OBR said in November there was about £25bn left to pay by 2057. About £18bn will be paid in the first five years.

It was thought the total Brexit bill would be smaller than £39billion because the numerous Brexit extensions meant that the total was decreased thanks to the UK’s contributions to the EU Budget.  

The Government promised that Brexit, which took legal effect on December 31 2020, would spell the end of huge sums being paid to Brussels.

The Withdrawal Agreement, which includes the financial settlement, was largely negotiated by Theresa May’s government.

It was agreed by Boris Johnson and Lord Frost after the Northern Ireland Protocol replaced the Irish "backstop".

The Brexit minister blamed negotiators under Theresa May as being responsible to a "very large degree" for issues with the Northern Ireland Protocol.

On Friday, Lord Frost was grilled in person by assembly members on Stormont’s Executive Office Committee, which is scrutinising issues arising from Brexit.